Power dipper trip



Sept. 8, 1931.

A. E. HCLCOMB POWER DIPPER TRIP Filed Nov. 12, 1927 auto emu Patented Sept. 8, 1931 UNITED STATES PATENT OFFICE- ALPHEUS E. HOLCOMB, OF MILWAUKEE, WISCONSIN, ASSIGNOR '10 KOEHRING COM- PANY, OF MILWAUKEE, WISCONSIN A CORPORATION rowEn DIPPER TRIP Application filed November 12, 1927. Serial No.'232,8 10.

This invention relates to a power dipper trip and particularly to a construction Wherein the dipper door is tripped for discharge by means of a power device such as may com- 5 prise a power driven trip cable windlng drum.

In the general arrangement of dipper trip cables or connections, they extend outwardly from theirwinding drum on the crane body or car to the dipper stick at its connection with the boom and thence downwardly beneath the boom to the dipper. In such construction, the rapid racking-in of the dipper causes a cable slack greater than can be taken up in the relatively slower winding-in movement of the trip cable drum and results in loss of time, while such slack is being rewound upon the drum, before tension can be secured for tripping and discharge. It also has been found that any accidental stoppage in the free running of the cable is liablerto result in a premature release of the door'trip. To avoid such objections, I have provided a construction wherein the trip cable is gradually slackened in the outward crowding movement of the dipper and is gradually tensioned in the more rapid inward racking travel so asto: maintain a taut cableready for immediate tripping action when the drum is shifted for that purpose. The outward crowding movement of the dipper is usually at a much less speed than the inward racking movement so that the slacking of the cable, incident to the outward movement is readily compensated for by the normal winding movement'of the'drum, that is, before it is shifted for power connection" suificient to operate the trip. If the free running of the cable be stopped,for any reason, in the movement of the drum and dipper, there is no danger of accidental tripping, since the slacking of the cable in the outward movement of the dipper prevents any tension on the trip I. and such tension does not reach a dangerous trip including a boom and a dipper carrydegree in the inward movement before the ing member mounted thereon for longitudinal movement, with a trip cable carried by the said member to effect a tensioning thereof during the inward racking movement of the W member.

A further object of the invention is to present a new arrangement of the trip cable,

mounted upon a dipper stick at a point above mounting of a dipper stickupon a boom and, I

thence, upward to a lever with a connection from said lever extending downward at the upper side of saidstick to a trip device.

Other and, further objects and advantages of the invention will be hereinafter set forth and thenovel features thereof defined by the appended claims. V.

I In the drawings: 7

' F gure 1'is an elevation of the invention applied and Figure 2 is a detailed enlarged section on line 2 -2 of- Figure 1.

Like numerals of reference refer to like parts in the figures of the drawings.

. The invention is adapted for various applicapivoted boom 12, supporting the usual dipper carrying member or stick l3,which is provided with a rack 14 cooperating with a gear 15 for imparting longitudinal movement to the stick; 'This gear 15is shown as driven by a cable connection 16 extending to a driving' means 17 at the housing. A dipper 18 at the lower end of the stick is provided with the usual discharge door 19 and connected by a cable QO extendingover a sheave 21*at the outer end of the-boom to asuitable winding drum in the housing. The parts so far described are of an ordinary construction and different means may be used for the crowding-out and racking-in movement of the dipper usual in this art.

A trip cable 22 extends from a Winding drum 23 outward to the boom and dipper stick. The drum 23 has a frictional engagement with a driving means that is normally very slight so that only sufficient power will be delivered to the drum to tension the trip cable 22 for the purpose of taking up slack caused by crowding-out movement. \Vhen the trip cable is to be availed of for tripping the dipper door the drum 23 is shifted by a movement of an operating member 24, which is in connection with the drum 23. A proper shifting of the drum causes it to engage the frictional driving connection with a greater pressure, whereby additional power is supplied, which is sufficient to trip the dipper door. The mechanism just described is clearly illustrated in application Serial No. 128,- 578, filed April 11, 1926'. The cable 22 extends over a sheave 25 supported at the point of the stickdriving connection to the boom by a stirrup 27 and, thence, extends upward to a lever 26 pivoted at the upper end of the dipper stick. From this lever a cable connection extends dow ward to a trip device 28. This device may be of any preferred character and is shown in Figure 2 as comprising a rock shaft 29, having at one end a lever 30 connected to the cable 27, and at its opposite end a similarly disposed lever 31, having a connection 32 with the ordinary trip latch upon the door 19 of the dipper. This arrangement disposes the connection 27 above the dipper stick and, therefore, provides more clearance. beneath the same than could be secured in the structures where the cable was disposed at the inner face of the stick.

The operation of the invention will be apparent from the foregoing description, from which it will be seen that in the outward crowding movement of the dipper there will be a gradual slackening of the trip cable, but as this movement is slow, the winding drum is able to take up such slack and maintain a taut connection. In the operation of the dipper, it is frequently desirable to rack thesame inward by a rapid movement and, owing to the connection of the trip cable at the outer end of the. stick, this inward movement exerts a gradually increasing tension and outward pull of the cable so that there is no danger of accidentally tripping the dipper door, but the trip cable is maintained in a taut condition so as to immediately operate such door, when a further rewinding of the cable is effected for that purpose.-

It will be apparent that the mechanism hereinbefore described provides for the reversing of the directions in which stresses are applied to the trip cable upon racking-in or crowding out motion being imparted to the dipper stick, as compared to the directions of such forces in other proposed types of dipper door trip mechanisms.

The control means 22-23 before referred to may be known types in which a door trip cable is slightly tensioned normally, or inpulled so to speak, to take up slack, and then placed under, greater special quick and positive tension to cause trip action of the said trip cable for door opening action.

Upon rackingifn movement of the dipper stick 13 the tension on the trip line 22 will be gradually increased as the speed of movement of the dipper stick increases, it being conventional practice in the operation of power excavators to rack in very rapidly.

Having thus described my invention what I claim as new, and desire to secure by Letters Patent of the United States, is:

1. In a dipper trip, a boom, a dipper stick mounted thereon for racking movement, cable take up means, a lever at the upper end of the stick, a cable extending from said cable take up means to said lever, and means for operatively connecting the lever and the door of a dipper.

2. In excavating apparatus, the combination with a boom, a dipper stick and dipper swingably mounted thereon, of cable means for tripping the dipper comprising a trip cable connected to the boom and extending to the free end of the dipper stick, and means associated with the dipper stick and connected to the trip cable at the free end of said dipper stick for effecting operation of the dipper door from said trip cable, said cable meansbeing tensioned in racking-in movements of the dipper stick.

3. A trip mechanism of the class described, comprising in combination with a boom, a dipper stick having a dipper mounted thereon, and a door for the dipper, of a trip cable for the dipper door associated with the boom and extending to the free end of the dipper stick, and connecting means associated with the dipper stick and to which said. trip cable is connected at the free end, including a cable for effecting operation of the dipper door from the trip cable.

4. In excavating apparatus, the combination with a boom, a dipper stick and dipper swingably mounted thereon, of a trip cable for tripping the dipper, slack take-up means connected to said cable, and means for connecting the cable to the stick and boom so as to train the cable toward the free end of the stick along one side thereof, and acable operatively connected to the trip cable and er:- tending along the opposite side toward the dipper whereby racking-in movements of the dipper stick will cause tension upon the trip line. I

5. In excavating apparatus, the combination with a boom, a dipper stick and dipper swingably mounted thereon, of a trip cable for tripping the dipper, slack take-up means connected to said cable, means for connecting the cable to the boom and to the dipper stick arranged so that a section of the cable extends outwardly toward the free end of the 7 stick, and separate connecting means extending from said free end and along the dipper stick toward the dipper, whereby in all racking-in movements of the stick tension is applied to the cable.

6. In excavating apparatus, the combination with a boom, a dipper stick and dipper swingably mounted thereon, of a trip cable for tripping the dipper, slack take-up means connected to said cable, means for connecting the cable to the boom adjacent to the mounting of the dipper stick thereon whereby a section of the cable is trained to extend along the stick toward the free end thereof, and a second cable connecting means on the stick extending along the boom to the dipper reversely in direction to the cable section aforesaid whereby racking-in movements of the stick draw the trip cable from the slack take-up means and racking-out movements release the cable for take-up action;

In testimony whereof I affix my signature.

ALPHEUS E. HOLCOMB. 

